BOSTON, Feb 2 (Reuters) - Prominent hedge funds including Dan Sundheim's D1 Capital Partners and Steve Cohen's Point72 Asset Management chalked up deep losses last month as hotly traded Gamestop hurt returns while others like Jason Mudrick's Mudrick Capital posted gains during January's turbulent trading, investors in the funds said on Tuesday. The bulk of January's hedge fund returns were influenced by a late-month rally in unloved stocks including GameStop and AMC Entertainment. The Standard & Poor's 500 index ended January down 1.1%, with the vaccine rollout and stimulus plans a large focus for the month.